The present invention concerns a process for the production of a telecentric light beam, that is, a set of beams formed by a single beam displaced absolutely parallel to itself, especially for the measurement of the dimension and/or the position of an object in the region of the deflection stroke of the light beam, wherein the light beam is deflected through an angular range at the focal point of an optical element and is turned by means of the optical element into the telecentric direction.
Such processes are known, wherein the periodic deflection of the light beam through a defined angle is effected by means of a multi-faceted rotating mirror. The optical element for turning the light beam into the telecentric direction, as well as a further optical element for turning the telecentric light beam onto an opto-electric transducer, are formed as relatively expensive lens systems. In spite of the high cost for these lens systems it is hardly possible to achieve the shifting of the telecentric light beam linearly or exactly according to a defined function, particular an angular function. The cost of the lens systems is especially high when a larger deflection stroke of the telecentric light beam is necessary for the measurement of larger objects.
A further disadvantage of the known process for the production of telecentric light beams lies in the fact that apart from the telecentric light beam serving for the exemplified dimensional measurement no portion of the beam is available that could be used for auxiliary purposes. The extraction of such a partial beam would be complicated and expensive.